Flexible diaphragm controlled valve

ABSTRACT

A multiport flexible diaphragm controlled valve is disclosed. The parts are all interconnected by low dead volume channels. The valve provides extremely fast response times, no moving parts other than the control diaphragm, operability over a wide range of operating conditions including high temperatures and is adaptable to use with all types of chromatography systems. The valve may also be utilized in a double sided configuration enabling two independent flow patterns to coexist simultaneously and be switched totally independent of one another.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,119,120 describes a fluid switch useful as a samplingdevice in chromatography systems for switching gaseous or liquid fluidstreams between two possible channels. The switch can be employed in twomodes. The first as a substitute for two position slider block valvesused previously in the art and in the second as a plurality ofinterconnected switching pairs to provide a plurality of switchingactions from a single control fluid switched source.

The aforesaid fluid switch comprises a series of paired enclosuresformed by two depressions in a first plate, each depression having aninlet and an outlet and an elastomeric diaphragm covering thedepressions. The diaphragm is held in place by a second plate having afirst control inlet opposite one depression and a second control inletopposite one depression and a second control inlet opposite the otherdepression. A fluid to be switched is connected into the inlets of thefirst plate in common. By alternatively applying a control fluid to onecontrol inlet and then the other of the second plate, the fluid to beswitched is switched from one inlet to the other by the diaphragmalternatively being deformed into one depression and then the other bythe control fluid so as to seal the inlet and outlet and thereby blockthe flow of fluid therethrough from the inlet. Thus, the paired switchvalves operate in series and when arranged in multiple arrays flow canbe directed to one or the other chambers in each pair but won't proceedfrom one pair to any other.

A similar multiport flexible diaphragm controlled fluid switching valveis described in Italian Pat. No. 603,986, issued Apr. 27, 1960. As wasthe case with the valve disclosed in U.S. Pat. No. 4,119,120 anddiscussed above the paired switch valves are linked in series and whenany one valve inlet and outlet are closed, by operation of the controldiaphragm then flow of fluid is not possible to other switch valvepairs. Additionally, the inlet and outlet channels are bored within theinternal portion of the support plate and thus do not provide a low deadvolume passage between the valve chambers.

Other flexible diaphragm controlled fluid valve systems are taught inBritish Pat. No. 977,364, published Dec. 9, 1964; U.S. Pat. No.3,095,746, issued July 2, 1963 and U.S. Pat. No. 3,057,594, issued Oct.9, 1962.

SUMMARY

The present invention describes a unique flexible diaphragm actuated,multiport valve, with a continuous low dead volume channel, which isconstantly swept during flow. This channel surrounds each port of thevalve and permits flow between open ports. It remains unobstructed toflow in any switching configuration. Thus, each port may beindependently opened or closed providing access or lack thereof, to thatportion of the channel surrounding each port. When two or more ports areindependently opened, the valve provides excellent flexibility in itsuse as a switching fluid flow valve between these independentlycontrolled ports. By fabricating this valve with a double sidedconfiguration, two independent flow patterns can exist at the same timeand be switched independently of one another.

A further feature of the valve of the present invention is the fact thatwith the exception of the minor motion of the diaphragm moving up anddown to permit the opening and closing the various ports, there are nomoving parts associated with its operation. By use of proper fabricationmaterials the valve can be fully functional and operational attemperatures exceeding 400° C.

Another feature of a preferred embodiment of the present valve involvesthe use of diaphragms with pre-formed bubble configurations located indirect opposing relationship to the peripheral channels around each portso that fluid flow through the channels will continue if other ports areopen even when the port in question is in a closed position. Thepreformed bubble shape in the diaphragm remains elevated in its relaxedposition.

DESCRIPTION OF THE DRAWINGS

FIG. 1 represents a inside face view of the front base plate of thevalve showing the multiple inlet ports with interconnected peripheralchannels surrounding each port.

FIG. 2 is a cross-sectional view of the assembled multiport valvebisecting two opposed ports, one in the open and the other in the closedposition.

FIG. 3 is an inside face view of the back plate showing the recesseseach of which may connect with an outside pressure source to providepressure to move the diaphragm down over the port opening.

FIG. 4 is a cross-sectional view of a single port depicting thepreformed bubble diaphragm configuration in the relaxed positionallowing flow between the port and the surrounding ring channel.

FIG. 5 is a cross-sectional view of a single port depicting thepreformed bubble diaphragm configuration in the pressurized or closedposition thus preventing flow through the port.

FIG. 6 is an inner face view depicting an alternate back plateconstruction which can be used in conjunction with a flat diaphragmconfiguration.

FIG. 7 is a frontal view of the spacer member used in conjunction withthe back plate shown in FIG. 6 allowing separation of the diaphragm andthe front plate above each port and corresponding surrounding groove.

FIG. 8 is a cross-sectional view of a single port depicting the flatdiaphragm and spacer member configuration when the valve port is in therelaxed or open position allowing fluid flow through the port.

FIG. 9 is a cross-sectional view of a single port depicting the flatdiaphragm and spacer member configuration when the valve port is in thepressurized or closed position preventing fluid flow through the portwithout affecting flow in the peripheral channel.

FIG. 10 is a cross-sectional view of the assembled multiport valve in adouble sided embodiment which permits two independent flow patternswithin the valve to exist simultaneously.

FIG. 11 is a schematic representation of the present multiport valve ina chromatographic system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed to an improved multiport, flexiblediaphragm actuated valve which is suited for use in conjunction withinstruments such as gas or liquid chromatographs. The improvements whichare incorporated in such valve are made evident by consideration of theaccompanying Figures which are discussed in detail below.

In FIG. 1, a top inside view of the front base plate which forms anintegral part of the valve construction is shown. The inside face 1 ofthe plate is provided with a continuous channel 2 recessed or cut intothe plate face and a series of clearance holes containing bolts as apossible method used in holding the valve components together andeffecting a gas tight seal where appropriate. The valve plates may alsobe held together by a weld or a swaged ring around the outside edge. Thechannel is comprised of peripheral channel portions 2A which surroundeach of the multiple inlet port opening 4 and interconnecting channelportions 2B which provide a path for fluid flow between adjacent channelrings. The channel is constructed to allow a continuously swept, lowdead volume connection between any two or more ports. Thecross-sectional area of the channel can be made proportional to thecross sectional area of the inlet ports thus minimizing the dead volume.

The front and back plates of the valve, along with diaphragm, in thisinstance, are secured by means of bolts passing through bolt holes 3.

In operation each port inlet is independently opened or closed by theapplication or release of pressure to the back side of the controldiaphragm. When the diaphragm is in its open position with respect toone port, flow of fluid is permitted to or from that port through itssurrounding continuous channel and may egress through one or more otheropen ports. Thus, the valve may be used either as a switching valvesince any switching combination is possible or when all or nearly allports are open, as a manifold.

FIG. 2 depicts a cross-sectional view of the multiport valve showing twoopposed ports. The front plate 5 and the back plate 6 are securedtogether by means of holding bolt 13 which passes through the center ofthe valve through clearance holes in both plates which are in directregistration with each other. The secured plates serve to clamp flexiblediaphragm 7A into position between the two plates and into closejuxtaposition to the access holes 4 and 4' to ports 11 and 11'respectively. They also serve to maintain a gas tight seal where needed.In the embodiment shown, the diaphragm passing through recess chamber 9,formed in the back plate to permit diaphragm movement, is in the relaxedor open position thus permitting fluid flow in either direction betweenperipheral channel 2A and port 11 through access hole 4. Use of thepreformed bubble shape for diaphragm 7A which remains elevated in itsrelaxed position facilities such freedom of flow even when pressure isalmost zero. Conversely, the portion of the diaphragm passing throughthe recess chamber 9' is in the pressurized or closed position caused bythe application of fluid pressure through pressure port 12' unto theback of the diaphragm which in turn contacts the access hole 4' servingto seal off fluid flow through port 11'.

Due to the relatively small cross-sectional area of channel 2A and 2A',the diaphragm does not enter into the channel when in the pressurized orclosed configuration. All recesses on the back plate, including 9 and9', are independent from one another.

In FIG. 3 a frontal view of the inner side of the back plate is shown.The face surface 14 of the back plate contains an equivalent number ofrecesses 9 as there are ports on the front plate and such recesses arearranged and constructed to be directly opposed to a corresponding portwhen the plates are assembled into the finished valve. The pressure portinlets 12 are seen centrally contained in each recess. A number ofmounting holes are provided to allow insertion of the bolts used tosecure the valve components and to make the device gas tight.

FIG. 4 provides a detailed view of a cross section of one port of themultiport valve. As above front plate 5 and back plate 6 are securedtogether to form the valve body with diaphragm 7A being centrallydisposed between the two plates. The diaphragm is in a preformed bubbleconfiguration and is in a relaxed or open position with respect toaccess hole 4 of port 11. To achieve this position fluid pressure isvented outwardly from recess 9 as indicated by directional arrow 16A.Fluid flow is now possible between port 11 via access hole 4 andperipheral channel 2A.

In FIG. 5 the section of the valve shown in the preceding Figure is inthe pressurized or closed position. Thus, flow from or to port opening 4is shut off from channel 2A. Flow through the channel will stillcontinue unobstructed if another two ports are in the open position. Toeffectuate this closed configuration, pressure fluid, such as compressedair, is directed through pressure port 12 as seen by direction arrow16B, to pressurize recess 9 so as to cover access hole 4.

FIG. 6 provides a frontal inside view of a back plate with analternative pressure port configuration. Ports 18 passing through theplate face 17 are the ports through which pressure fluid flows into thevalve. When the valve is assembled the ports 18 are arranged andconstructed to be aligned with access holes 4 of the front plate. Thisalternative back plate configuration is utilized with a flat diaphragmembodiment.

As a further component for use with the flat diaphragm embodiment, FIG.7 depicts a frontal view of a spacer 23 having mounting holes 3 whichregister with corresponding holes in the front and back plates in theassembled valve and multiple holes 22 which are aligned with the portsin the assembled valve.

FIG. 8 is a cross-sectional view of a single port section of anassembled valve utilizing a flat diaphragm embodiment. Thus, flatdiaphragm 7B is supported between back plate 19 and front plate 5 withthe port configuration of the back plate being in the alternativeconfiguration described above in FIG. 6. Spacer 21 is provided toseparate the front and back plates and to leave a gap between thediaphragm and the front plate surface 1 when the diaphragm is in arelaxed or unpressurized position. This permits fluid flow betweenaccess hole 4 of port 11 and peripheral channel 2A. In this openposition, pressure has been vented through pressure port 20 in thedirection indicated by arrow 16A.

In FIG. 9 the flat diaphragm embodiment depicted in the previous Figureis shown in the closed position. This is accomplished by introducingpressurized fluid through pressure port 20 in the direction indicated byarrow 16B. The pressure forces diaphragm 7B to seal off the access hole4 moving the diaphragm away from the face 17 of back plate 19. Asbefore, peripheral channel 2A remains unblocked and fluid flow betweenany two or more other open ports will continue independently of theclosing of the port in this Figure.

Turning to FIG. 10 there is shown a cross-sectional view of anotherembodiment of the improved valve of the present invention wherein adouble sided valve is shown. In this embodiment bolt 13A secures twoback plates 6A and 6B to either side of a double sided front plate 24.The groove channel pattern on each face of plate 24 is identical to thatof FIG. 1. The double sided front ports, such as 11A and 11B. Each portis distinguished in having a through channel such as 25A and 25B whichopens on both faces of front plate 24 through access holes such as 27Aand 27B. The through channels and access holes provide access to fluidflow to or from ports 11A and 11B to the peripheral channels around theports such as 2A and 2A' depending on whether or nor the respectivediaphragms such as 7A or 7A' are in the open or closed position. Eachdiaphragm is under separate and independent fluid pressure controlthrough pressure fluid inlets such as 12A, 12B, 12C and 12D.

Thus in the embodiment depicted in the subject Figure access hole 27A isclosed to fluid flow by the closing action of diaphragm 7A which isacted on by positive fluid pressure introduced through pressure inlet12D. On the other hand fluid flow to or from port 11B is possible viathrough channel 25B; access hole 27B the peripheral channel provided onface 1B of front plate 24 since diaphragm 7A' is in the open position.In this embodiment, diaphragm 7A and 7A' are shown in the preformedbubble configuration. Since all ports in the double sided valveembodiment are independently opened or closed, it is possible toestablish two independent flow patterns existing simultaneously.

FIG. 11 provides a schematic view of a multiport valve of the presentinvention used in a relatively complex chromatographic system. Thus, forexample all of the switching needs for the full operation of thismultidimensional gas chromatographic system can be met by use of thepresent invention consisting of, in this instance, a double side 6 portvalve whose basic configuration is similar to that shown in FIG. 10.Each port in FIG. 10 enters through the edge of plate 24, branchinginside the plate into a "T" formation, each side of which opens out toeach face, 1A and 1B, of plate 24. Any or all of the bubble diaphragmsadjacent to port openings of both sides of the valve may be actuatedcompletely independent of one another. This can be accomplished byutilizing a pressure source for twelve individually operated solenoidvalves. Each solenoid valve is connected to a tube through eitherbackplate. Thus for example, one solenoid valve is connected to tube 12Din FIG. 10. When that solenoid valve is actuated, pressure is allowed toflow through 12D, forcing down the bubbled portion of diaphragm 7A whichsits directly over opening 27A. This prevents flow from port 11B throughopening 27A. By deactivating the solenoid valve, pressure is releasedthrough 12D allowing the bubbled portion of diaphragm 7A above opening27A to lift off the valve face 1A. Flow may then proceed between opening27A and its surrounding channel 2A. The twelve solenoid valves may beswitched by use of a microprocessor, thus permitting entire switchingstates to be preprogrammed.

Since the valve is double sided, two flow patterns may existsimultaneously and independently from one another on opposite sides ofthe valve. One side of the valve will be referred to as side A(analogous to valve face 1A in FIG. 10), the other as side B (analogousto valve face 1B in FIG. 10) in the following discussion.

The chromatographic system shown in FIG. 11, for example, contains twocolumns, two detectors and two traps. If desired, trap 2 may be replacedby a third detector or a third column if necessary. Each of the columnscontains a stationary phase of differing polarity from the other.

The column configuration described above may be used in conjunction withpreparative, analytical and/or capillary columns or any combinationthereof. Thus, for example:

    ______________________________________                                        First Column           Second Column                                          ______________________________________                                        Packed (Analytical or Preparative)                                                                   Analytical or                                          or Capillary           Capillary                                              ______________________________________                                    

Therefore, suitable combinations include

Packed and Capillary or

Capillary and Capillary Columns

The detectors useful in conjunction with the system described above maybe any suitable detector used in the chromatographic arts for thatpurpose, i.e.

Flame Ionization

Electron Capture

Nitrogen/Phosphorus

Thermal Conductivity

Coulometric

Gas Density Balance

Ultra Violet

Fluorescence

Mass Spectrometer

Infra-Red and the like.

With the use of the valve system depicted in FIG. 11 several switchingconfigurations will be described these are:

1. Column Monitoring. Switching the effluent from Column 1 to Detector 1and/or from Column 2 to Detector 2.

A sample is injected through injector port 31. It is chromatographed oncolumn 1 using carrier gas supply 1. The separated component bands aredetected as they are eluted from the end of column 1 by usingdetector 1. Carrier gas 1 is fed into the system through open valve 30.Valve 33 is closed. Makeup gas 2 continues to flow into detectors 1 and2. The end of column 1 is connected to port 41 on multiport valve 50.The input to detector 1 is connected to port 42 on valve 50. Theswitching configuration for valve 50 is as follows: Ports 41 and 42 areopen on Side A of the valve. All other ports on Side A are closed bypressure applied to the backside of the diaphragm over appropriate portopenings. Ports 43 and 45 are open on Side B. All other ports on Side Bare closed. With this configuration, the output from column 1 is sweptthrough the continuous channel surrounding the opened ports and flowsinto detector 1 on Side A with a minimal dead volume contribution fromthe valve. This is particularly important when capillary columns areemployed in the system. Simultaneously, carrier gas 2 flowing throughopen valve 39, is flushing column 2 on Side B.

In a manner similar to that described for column 1 above, column 2 maybe independently and simultaneously monitored along with column 1. Asample is injected through injector port 38. Ports 43 and 45 are open onSide B, all other ports on this side are closed. Carrier gas 2 which isfed in through open valve 39, sweeps the injected sample plug throughthe continuous channel on Side B onto column 2. The chromatographedcomponent bands as they emerge from the exit of column 2 are detected bydetector 2. With this configuration, these events can occur while column1 is being monitored independently if desired, since ports 41 and 42 canbe the only ports opened on Side A.

2. Sample Component Transfer

At times, it is desirous to direct some sample component bands whichhave been chromatographed and are emerging from column 1 to the top ofcolumn 2, with minimal distortion or spreading of the bands particularlywhen capillary columns are used. To accomplish this, at the appropriatetime, ports 41 and 45 are opened on Side A. All other ports on this sideare closed. Ports 42 and 43 are opened on side B. All other ports onside B are closed. Valve 30 is opened and valve 33 is closed. Make upgas 2 continues to flow into detectors 1 and 2. Flow then proceeds fromthe outlet of column 1 to the inlet of column 2 on side A of the valveand carrier gas 2 is sweeping detector 1 through side B of the valve. Itis noted here that once the desired sample band has been transferredfrom column 1 to column 2, one may return to the switching configurationused for Column Monitoring with both columns and detectors operatedsimultaneously and independently.

3. Sample Component Trapping Transfer of Chromatographic Bands FromColumn 1 to Trap 1 and/or Trap 2

Appropriate narrow bore tubes are used as traps and one side of eachtube is connected to ports 44 and 46 of the valve respectively. Theother side of the traps may either be vented or be swept with carriergas depending on the position of valves 37 and 40. The trap, being oflow mass, may also be rapidly heated or cooled. For this switchingconfiguration, the trap is cooled so that any sample solutes entering itwill condense out on the walls of the trap while the carrier gas isallowed to pass through the trap and exit by means of the vent port viavalve 37 and/or 40. To accomplish this, for example, ports 41 and 44 areopen on side A of valve 50. All other ports on side A are closed. Ports43 and 45 are open on side B of the valve. All remaining ports on side Bare closed. Valve 37 is switched so that the carrier gas emerging fromcolumn 1 is vented through vent 1. In this configuration, the outputflow of column 1 enters the inlet of trap 1 through side A of the valve.Column 2 is flushed with carrier gas 2 through side B of the valve. In asimilar manner, a different segment of the chromatographic effluentleaving column 1 may be selectively condensed in trap 2. Here, ports 41and 46 are open on side A of valve 50. All other ports on side A areclosed. Ports 43 and 45 are open on side B of the valve. All remainingports on side B are closed. Valve 40 is switched so that the carrier gasemerging from column 1 is vented through vent 2.

4. Transfer of Sample Components from Trap 1 and/or Trap 2 to Column 2

After a selected sample component or components have been condensed onthe cooled walls of trap 1, these components may be released from thewalls by a rapid heating of trap 1. Port 44 and 45 on side B of valve 50are opened. All other ports on side B are closed. Valve 37 is switchedso that carrier gas 3 flows into trap 1 as trap 1 is being heated. Ports41 and 42 on side A of valve 50 are open. All remaining ports on side Aare closed. In this switching pattern, the output of trap 1 is sent intocolumn 2 through side B. Detector 1 is connected to the output of column1 through side A.

Similarly, other components that have been selectively condensed in trap2 may be transferred to column 2. Thus, after trapping of thechromatographed band(s) in trap 2, ports 45 and 46 on Side B of valve 50are opened. All other ports on side B are closed. Valve 40 is switchedso that carrier gas 4 flows into trap 2 as trap 2 is being heated. Ports41 and 42 on Side A of valve 50 are open. All remaining ports on Side Aare closed. In this switching pattern, the output of trap 2 is sent intocolumn 2 through side B. Detector 1 is connected to the output of column1 through side A.

5. Back flushing of certain sample components still residing on Column 1

Ports 41 and 43 are open on side A of valve 50. All other ports on sideA are closed. Valve 30 is closed and valve 33 is open. Thus the outputbackflushed out of column 1 will flow through and be sensed bydetector 1. Ports 43 and 45 are open on side B of the valve. All otherports on side B are closed. Thus, in this configuration, with valve 39open, carrier gas 2 backflushes column 1 through side A and forwardflushes column 2 through side B. (Column 2 may also be flushed withcarrier gas 3 through trap 1 instead of utilizing carrier gas 2, i.e.,port 44 is open, port 43 is closed on side B, and valve 37 is openconnecting carrier gas 3 to trap 1.

6. Solvent flushing

In this embodiment, the sample is injected into the first injector 31and moves onto column 1 to be chromatographed. At this point, valve 50is in switching configuration described under Column Monitoring. Whenthe solvent peak is detected in detector 1, valve 50 is then switched tothe solvent flushing mode. Ports 43 and 42 on side B of the valve areopen and all other ports on side B are closed. Ports 41 and 45 are openopn side A of the valve (trap 1 may be open to flow instead of column2). All other ports on side A are closed. Also port 41 may be completelyclosed after detection of the solvent peak. Carrier gas 2 is switched toflush the solvent peak from detector 1. (It can also be used to flushcolumn 2). Then port 4 on side A of the valve may be opened so thatchromatographic bands emerging from column 1 devoid of most if not allof the solvent can then either be detected in detector 1, and/or trappedin the cooled trap 1, and/or transferred to column 2 using switchingconfigurations 1, 3 or 2 respectively as explained above.

Certainly many more switching possibilities other than those mentionedabove are possible with the system shown in FIG. 11.

The fluid pressure actuating the diaphragms can be gas or liquid. Alsomechanical actuation is possible in extremely high pressure applicationssuch as liquid chromatography. For fluid actuation, the pressure can besupplied from any convenient source and switched through a multiplesolenoid manifold, to each pressure fluid inlet in the multiport valve.

The pressure fluid used for controlling the diaphragm position ispreferably a gas, such as an inert gas, for example, argon, helium,nitrogen, carbon dioxide, compressed air or any other gas conventionallyutilized in valve control. The gas can be provided from any convenientsource preferably a gas cylinder and distributed through a multiplesolenoid valved manifold to each pressure fluid inlet in the multiportvalve.

Materials for use in construction of the valve body include metals suchas stainless steel or a thermosetting, chemically inert, and heatresistant plastic such as Kel-F (a polymer of chlorotrifluoroethylene).The diaphragm may be produced from a thin, flexible, chemically-inertand heat resistant plastic such as Mylar (a polyester) film), Teflon (apolytetrafluorethylene film), polyimide, Kalrez (a perfluoroelastomer)and the like; or silicone rubber either alone or coated with saidplastic materials; or a thin metallic sheet either alone or coated orlaminated with said plastic materials. For use at temperatures of 250°C. or above, an all metallic construction of the valve body anddiaphragm is preferred.

The introduction of the preformed bubbles in the diaphragm in positionsregistering with each port can be readily accomplished by molding orstamping the bubbles into the diaphragm film prior to fabrication intothe valve.

Suitable carrier gases for use in the instant valves include the inertgases such as helium, nitrogen, argon and the like or hydrogen.

While the valve of the invention has been described utilizing up to sixseparate ports it is within the scope of the invention to employ feweror greater numbers of ports. Similarly while the ports have been shownin circular configuration they may be used in any convenient geometricrelationship without materially affecting performance. Furthermore, theperipheral channels can be interconnected by direct pathways instead ofor in addition to the circumferential connecting between adjacent portsdepicted herein.

Thus, the valve of the present invention is seen to provide a number ofadvantages in construction and operation as follows:

1. It is a very low dead volume valve due to presence of a continuouschannel with a small cross sectional area which is completely andcontinuously swept when two or more ports are opened.

2. The shape of the diaphragm contributes negligible dead volume betweenthe port opening and its surrounding channel ring.

3. With the exception of the small excursion of the diaphragm moving upand down, there are no moving parts associated with the operation ofthis valve. Slider or rotor parts are absent. Under these circumstancescertain materials, for example, gold, which would ordinarily seize uponsliding, can be readily utilized in the construction of the valve.

4. The valve can be fabricated from materials which permit it to befully functional and operational at temperatures exceeding 400° C.

5. The valve surfaces, if fabricated from metal, for example, may berendered to be relatively inert chemically by the application of anappropriate film of a relative inert material such as gold deposited onthose surfaces exposed to sample fluid or gas.

6. The configuration of the valve and its dimensions may be so arrangedthereby permitting it to operate in most if not all areas ofchromatography. For example, on the one hand, with relatively smalleffluents from capillary columns which may be efficiently andeffectively switched and transferred to different detectors, differentcolumns, traps, collecting devices, and to other instruments, forexample, such as a mass spectrometer. Similarly, relatively largeeffluents from analytical, semi preparative, or preparativechromatographic columns can also be efficiently and effectively handledin a like manner by the utilization of the basic configuration of thevalve with small changes in the size of the continuous channel, the portopenings and the diaphragm and its surrounding area.

7. By the appropriate choice of diaphragm material and thickness, andthe appropriate choice of adequate shut off pressure, the valve can bemade to function at pressures extending up to 2000-5000 psi, ifnecessary.

8. The configuration of the valve permits independent and rapidswitching to the on or off positions of any combination of ports withina fraction of a second. The switching mechanism lends itself to theautomated control of this function by, for example, the use ofmicroprocessor or computer controlled solenoid valve or appropriatefluidic control systems.

9. The valve can be made relatively small and of low mass so that if itis used in chromatography, where the temperature of the chromatographicsystem may be raised or lowered rapidly, the temperature of the valvewill not appreciably lag behind that of the surrounding media.

10. The diaphragm of this valve may be actuated by a number of methods,for example, force applied by fluid pressure or mechanical means.

11. The valve can be used with minor changes to effectively operateunder vacuum and be used for example in mass spectrometry or combinedgas chromatography-mass spectrometry instruments.

12. The working principles of the present invention permits many formsof the valve to be realized. The two described herein are a single sidedand double sided six port valve.

I claim:
 1. An improved fluid pressure controlled diaphragm actuatedmultiport valve comprising:(a) a first plate having a multiplicity ofcontrol fluid inlet means passing through said first plate each of saidcontrol fluid inlet means being connectable to a source of control fluidunder pressure, and under independent pressure control; (b) a secondplate assembled adjacent said first plate having a multiplicity of fluidconduct means passing through said second plate, each of said fluidconduit means opening opposite a corresponding control fluid inlet meansin said first plate said second plate further having a multiplicity ofoperatively interconnected, low dead volume fluid channel means on itsinner surface peripherally surrounding each of said fluid conduit means;(c) a flexible diaphragm means disposed between said first plate andsaid second plate when said plates are assembled adjacent one another,said diaphragm means being so arranged and constructed as to seal anyfluid conduit means to fluid flow when said corresponding control fluidinlet means is open to control fluid under pressure, wherein saidchannel means are in independent operative fluid flow connection witheach said fluid conduit means when said diaphragm is not in sealingposition with respect to said fluid conduit means and are not inoperative fluid flow connection with each said fluid conduit means whensaid diaphragm is in sealing position, wherein further said channelmeans are so arranged and constructed to maintain operative fluid flowconnection between any of said fluid conduit means which are not sealed;and (d) means for holding said first plate, said second plate and saiddiaphragm in assembled adjacent relationship.
 2. The improved valve ofclaim 1 wherein said diaphragm contains preformed bubble membersarranged to correspond in position to each of said fluid conduit means.3. The improved valve of claim 1 wherein two of said first plates areprovided, one on each side of said second plate and said fluid conduitmeans in said second plate are each bifurcated to provide an opening ateach side of said second plate, each of said openings being incorresponding positions to a control fluid inlet means in said firstplates to allow independent sealing or opening of said openings by saiddiaphragm to thus provide a doubly faced valve.
 4. A chromatographsystem comprising the improved valve of claim 3, multiplechromatographic columns each having an inlet and an outlet and multipledetector means wherein a corresponding number of said fluid conduitmeans are each operatively connected to each of said outlets and acorresponding number of other said fluid conduit means are eachoperatively connected to each said detector means.
 5. The improved valveof claim 1 wherein said fluid conduit means are in a circularconfiguration within said second plate and said fluid channel means arecircularly disposed around the periphery of each said fluid conduitmeans.
 6. The improved valve of claim 1 wherein said valve componentsand diaphragm are metallic thereby allowing operation at temperatures inexcess of 250° C.
 7. A chromatograph system comprising the improvedvalve of claim 1, a chromatographic column having an inlet and an outletand a detector means wherein at least one of said fluid conduit means isoperatively connected to said outlet of said chromatographic column andat least one other of said fluid conduit means is operatively connectedto said detector means.